1. Field of the Invention
This invention relates generally to improvements in hammer bank assemblies useful in high-speed impact printers of the type generally employed in data processing systems, and more particularly to an improvement in the manner of mounting one of such hammers within said hammer bank assembly.
2. Description of the Prior Art
U.S. Pat. No. 3,279,362 shows an improved hammer configuration in which a flat rigid coil structure, carrying an impact tip thereon, is supported on a pair of flexible conductive spring members for substantially rotational movement about a horizontal axis extending perpendiculr to the plane of the coil structure. The coil is disposed within the field of a permanent magnet so that when energized, a force is developed on the coil structure to rotate it from a rest position to an impact position against a character drum mounted for rotation about an axis also extending perpendicular to the plane of the coil structure. The conductive spring members return the hammer to its rest position when the coil is de-energized.
U.S. Pat. No. 3,643,595 discloses further improvement in the manner of assembling a plurality of such hammers into a hammer bank assembly. In this assembly, each of the hammer modules is mounted to the frame using a bolt. Such a device, when operated at the high printing speeds of modern line printing devices, has beern found to be subject to vibrational failure in the flexible conductive spring members and at the supporting structure of the hammer at which they are attached.
In an attempt to alleviate such high-speed vibrational difficulties, U.s. Pat. No. 4,395,945 discloses the incorporation of a foot member through which the flexible conductive spring members are passed prior to their respective terminations in a circuitry portion of the printer mechanism. The flexible conductive spring members are bonded through the foot member and the foot member is permitted a limited motion with respect to the frame of the printer assembly to enable absorption of some fo the damaging vibration resulting from high-speed printing. However, recent increases in the desired and achievable printing energy rates of such printing assemblies tend to produce vibrations within the flexible conductive spring members that approach frequencies within the ultrasonic machining range. Thus, at such higher printing energies, the high frequency vibrations in the flexible conductive spring members can be seen to significantly damage the flexible conductive spring members at their junctions with the foot member. Moreover, a significant level of the high frequency vibrations are transmitted through the foot member by the flexible conductive spring members which may often result in the breaking of one or more solder interconnections with wires attached to the flexible conductive spring members at their free ends.